node-api/glue/stats.go

package glue

import (
	"log"

	"github.com/jinzhu/gorm"
	"github.com/rosti-cz/node-api/apps"
	docker "github.com/rosti-cz/node-api/containers"
)

// StatsProcessor covers all methods that are needed
// to gather information about application containers.
type StatsProcessor struct {
	DB *gorm.DB
}

// returns instance of getAppProcessor
func (s *StatsProcessor) getAppProcessor() apps.AppsProcessor {
	processor := apps.AppsProcessor{
		DB: s.DB,
	}
	processor.Init()
	return processor
}

// updateUsage updates various resource usage of the container/app in the database
func (s *StatsProcessor) UpdateUsage(name string) error {
	processor := s.getAppProcessor()

	app, err := processor.Get(name)
	if err != nil {
		return err
	}

	container := docker.Container{
		App: &app,
	}

	state, err := container.GetState()
	if err != nil {
		return err
	}

	err = processor.UpdateResources(
		name,
		state.State,
		state.CPUUsage,
		state.MemoryUsage,
		state.DiskUsageBytes,
		state.DiskUsageInodes,
		state.Flags,
	)

	return err
}

// Updates only container's state. Check current status of the container and saves it into the database.
func (s *StatsProcessor) UpdateState(name string) error {
	processor := s.getAppProcessor()
	app, err := processor.Get(name)
	if err != nil {
		return err
	}

	container := docker.Container{
		App: &app,
	}
	state, err := container.Status()
	if err != nil {
		return err
	}

	err = processor.UpdateState(
		app.Name,
		state,
	)
	return err
}

// gatherStats loops over all applications and calls updateUsage to write various metric into the database.
func (s *StatsProcessor) GatherStats() error {
	processor := s.getAppProcessor()
	appList, err := processor.List()
	if err != nil {
		return err
	}

	for _, app := range appList {
		err := s.UpdateUsage(app.Name)
		if err != nil {
			log.Println("STATS ERROR:", err.Error())
		}
	}

	return nil
}

// gatherStates loops over all apps and updates their container state
func (s *StatsProcessor) GatherStates() error {
	processor := s.getAppProcessor()
	appList, err := processor.List()
	if err != nil {
		return err
	}

	for _, app := range appList {
		err := s.UpdateState(app.Name)
		if err != nil {
			log.Println("STATE ERROR:", err.Error())
		}
	}

	return nil
}